writing messages which are easy to translate

[Rick Hillegas <ri...@oracle.com>]

I have added some guidelines on how to write messages which are easy to 
translate: http://wiki.apache.org/db-derby/LocalizingDerbyMessages

In addition, I have improved the advice about how to write message 
descriptors for the engine messages defined in messages.xml: 
http://db.apache.org/derby/manuals/messages.html . In particular, please 
note the advice about the order of <arg> elements in that file. Getting 
that order correct ensures that the ReferenceGuide will provide 
meaningful descriptions of the engine messages.

Thanks,
-Rick